A possible laser experiment for observation of photon-photon scattering in vacuum

An analysis is made of the possibility of using lasers in experimental studies of the scattering of photons by photons in vacuum. The minimum energy of each of the two lasers, required by the experimental conditions, is ~3×10⁸ J for ultraviolet radiation if the pulse duration is 5×10^–13 sec and the laser beams have the diffraction-limit divergence. The parameters obtained in this analysis indicate that the great experimental difficulties are likely to be encountered. A possibility is studied also of the formation with the aid of lasers of x- or γ-ray pulses which would collide in vacuum. It is shown that it would be much more convenient to use γ rays because it would then be sufficient to use laser systems with an energy of ~10⁶ J per pulse and the requirements to be satisfied by such pulses would be less stringent than in the optical wavelength range.